Principle
Rather than quantizing the absolute value of the input analog waveform, delta modulation quantizes the difference between the current and the previous step, as shown in the block diagram in Fig. 1.
The modulator is made by a quantizer which converts the difference between the input signal and the average of the previous steps. In its simplest form, the quantizer can be realized with a comparator referenced to 0 (two levels quantizer), whose output is 1 or 0 if the input signal is positive or negative. It is also a bit-quantizer as it quantizes only a bit at a time. The demodulator is simply an integrator (like the one in the feedback loop) whose output rises or falls with each 1 or 0 received. The integrator itself constitutes a low-pass filter.
Read more about this topic: Delta Modulation
Famous quotes containing the word principle:
“You may call a jay a bird. Well, so he is, in a measure—because he’s got feathers on him, and don’t belong to no church, perhaps; but otherwise he is just as much a human as you be. And I’ll tell you for why. A jay’s gifts and instincts, and feelings, and interests, cover the whole ground. A jay hasn’t got any more principle than a Congressman.”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)
“The principle of the brotherhood of man is ... narcissistic ... for the grounds for that love have always been the assumption that we ought to realize that we are the same the whole world over.”
—Germaine Greer (b. 1939)
“Well, you Yankees and your holy principle about savin’ the Union. You’re plunderin’ pirates that’s what. Well, you think there’s no Confederate army where you’re goin’. You think our boys are asleep down here. Well, they’ll catch up to you and they’ll cut you to pieces you, you nameless, fatherless scum. I wish I could be there to see it.”
—John Lee Mahin (1902–1984)